Chapter 22 Μ Pd78P014, 78P014Y; Internal Memory Size Switching Register - NEC 78014Y Series User Manual

The µ PD78P014 and 78P014Y are versions which incorporate a one-time programmable PROM or an EPROM
enabled for program write, erase and rewrite. Table 22-1 lists differences between µ PD78P014, 78P014Y and mask
ROM version.
Internal ROM configuration
Internal ROM capacity
Internal high-speed RAM capacity
Internal ROM and internal high-speed
RAM by memory size select register
IC pin
V pin
PP
P60 to P63 pin on-chip pull-up resistor
internal mask option
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Electrical specification
Note When RESET is input, the internal PROM capacity is set to 32 Kbytes, internal high-speed RAM capacity to
1024 bytes.
Caution

22.1 Internal Memory Size Switching Register

The µ PD78P014 and 78P014Y can select the internal memory capacity with the internal memory size switching
register (IMS). The same memory mapping as that of the mask ROM version with a different internal memory capacity
is possible by setting IMS.
In order to make the memory maps of µ PD78P014 and 78P014Y identical to a mask ROM version, the value at
the time the mask ROM version is reset must be set to IMS.
For the mask ROM version, IMS does not need to be set.
IMS is set with an 8-bit memory manipulation instruction.
The value of IMS becomes the value shown in Table 22-2, at RESET.
Caution
CHAPTER 22 µ PD78P014, 78P014Y
Table 22-1. Differences between µ PD78P014, 78P014Y, and Mask ROM Version
Item
The noise resistance and noise radiation differs between PROM versions and mask ROM versions.
If considering replacing PROM versions with mask ROM versions during the process from trial
manufacturing to mass production, evaluate the CS versions (not ES versions) of mask ROM
versions carefully.
To use a mask ROM version, do not set a value other than those shown in Table 22-2 to IMS.
CHAPTER 22 µ PD78P014, 78P014Y
µ PD78P014, 78P014Y
One-time PROM/EPROM
32 Kbytes
1024 bytes
Note
Enable
None
Available
None
Refer to the data sheet for each part number.
Mask ROM Version
Mask ROM
µ PD78011B, 78011BY:
8 Kbytes
µ PD78012B, 78012BY:
16 Kbytes
µ PD78013, 78013Y:
24 Kbytes
µ PD78014, 78014Y:
32 Kbytes
µ PD78011B, 78011BY:
512 bytes
µ PD78012B, 78012BY:
512 bytes
µ PD78013, 78013Y:
1024 bytes
µ PD78014, 78014Y:
1024 bytes
Disable
Available
None
Available
495